Ocorrência e caracterização morfológica de hemosporídeos em morcegos coletados em Montes Claros, Minas Gerais, Brasil

Abstract

The order Haemosporida is composed of more than 500 species of parasites that infect a wide range of vertebrate hosts, such as birds, reptiles, primates and bats. Haemosporidian parasites are widely distributed around the globe and very abundant in wildlife animal infections. These parasites might cause severe effects even in chronic infections, reducing life expectancy, survival and fitness of their hosts. Bats are fundamental organisms for the functioning of the ecosystem, since they perform a series of essential services for its maintenance, such as pollination, dispersion of fruits and seeds and population control of insects. However, little is known about the infection of bats by haemosporidians, especially in New World. The objective of this work was to evaluate the presence of haemosporidian parasites in Brazilian bats and to identify the genera of these hemoparasites. Possible associations between the presence of haemosporidian infections and biological characteristics of its hosts were also investigated. Thus, it was evaluated whether the season of year and host sex influence the occurrence of haemosporidian and if different species present variation in susceptibility to this infection. I also evaluated whether body condition of infected bats is lower than that observed for uninfected bats. For this purpose, 247 bats were captured in the municipality of Montes Claros, Minas Gerais. Measurements, sexing, blood collection and at least one blood smear were performed for each animal. Blood and blood smears were used for molecular diagnosis (amplification by PCR of 196 pairs of the ribosomal SSU gene) and morphological (microscopic observation) of haemosporidian. 208 individuals had smears of sufficient quality for analysis by microscopy. To estimate the infection rate, only individuals with viable slides were considered in the analysis, considering a minimum of 50 fields with a 400x increase and 200 fields with a 1000x increase for each bat. The body condition of the animals was also evaluated by weight / forearm ratio. In addition, I used five different molecular amplifications to sequence the parasites found in bats, however, no parasite was successfully sequenced. The occurrence of haemosporidian parasites in bats, considering the molecular and morphological diagnosis, was 6.44% (13/208). Among the positive smears, at least one parasite form (trophozoite, schizont or gametocyte) was observed. Nevertheless, detected parasitemias were often (10 out of 13) low (<1%) indicating a chronic infection status among the bats analyzed. The occurrence of haemosporidiana between the sexes was similar (p = 0.16, F = 5). However, haemosporidian occurrence differed between the season of year (p = 0.004, F = 6), being higher during the rainy season. Moreover, the infection also varied among species of bats evaluated (0 <0.0001, F = 18). The occurrence of hemosporids was significantly higher among vespertilionidae bats (21.5%) compared to filostomids (5.2%), with Myotis nigricans being the most parasitized species (23%). The weight / forearm ratio was also lower in infected animals, indicating lower body condition in bats infected with hemosporids (F = 170, p = 0.007). These data indicate that even in chronic infections, bats may be negatively affected by haemosporidian. We emphasize the need for new studies to characterize the role of these infections in the structuring of neotropical bat communities.